Coast Resorts Open Roads Forum: Towing: New Andersen WD hitch

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Topic: New Andersen WD hitch

Posted By: Ron Gratz on 05/25/12 04:51pm

BenK wrote:

renojack wrote:

snip...Where does the claim that the stock Chevy hitch absorbs weight distribution come from. I had the hitch checked an all is in order as far as loose or craced welds.

What happens is that the receiver pin box assembly bends on the round cross bar to 'consume' WD forces till it reaches its limits...then it will transfer (distribute) the WD forces.---

Every receiver will undergo some degree of pitch-axis rotation (twisting) when subjected to the pitch-axis torque generated by a WDH. The amount of rotation depends on the receiver's torsional stiffness and the magnitude of applied torque.

A receiver does not "'consume' WD forces until it reaches its limits". The torque which is applied to the hitch head by the WD bars is transmitted to the receiver via the drawbar and further is transmitted to the TV via the receiver.

If the torque is great enough to stress the receiver's steel to its yield point, the receiver will experience some degree of permanent rotation. This might or might not be great enough to detect visually.

Even if the receiver is stressed to its yield point (but not as far as its ultimate strength), it does not 'consume' WD torque. It still will transmit whatever torque is generated by the WD bars. However, if there is enough receiver rotation, you might find you need to increase the rearward tilt of the ball mount or decrease the number of links under tension -- but you will be able to load the bars and transfer load.

So, actually, the receiver will transfer all applied torque until it reaches its ultimate strength. Then it will undergo excessive rotation with decreasing transfer of torque, and eventually will fail if the rotation becomes great enough.

If cracks develop at critical locations, then the amount of torque required to produce yield stress or ultimate load will decrease.

Ron

Posted By: Ron Gratz on 05/25/12 05:13pm

BenK wrote:

First reported here below and is of a GMT800 8.1L Suburban just like the OPs:

Hitch Failure, the first report in 2003

This the first image on any forum that I know of and from the above
thread
[image]

Ben,

There is no evidence to support the assertion that the hitch failure shown above was due to "WD forces".

Instead, people who take the time to read Burbman's description likely will conclude (as Burbman did) that the failure was due to yaw-axis torque and lateral force generated by a pivot point projection hitch.

Ron

Posted By: BarneyS on 05/25/12 06:32pm

Ron, Even if it were caused by a pivot projection hitch, the receiver should not have failed. I think that is the point that Ben is making. Besides that, there have been MANY other posts about failures and bending of the GM hitch of certain years by using standard WD hitches, as I'm sure you are aware of. I am not aware of other makes of hitches failing like those years GM hitches did - regardless of type of WD hitch used. Renojack asked about where the claim came from about GM round tube hitches, and Ben answered him very well in my opinion.
Barney

2004 Sunnybrook Titan 30FKS TT
Hensley "Arrow" 1400# hitch (Sold)
Not towing now.
Former tow vehicles were 2016 Ram 2500 CTD, 2002 Ford F250, 7.3 PSD, 1997 Ram 2500 5.9 gas engine

Posted By: springfield5 on 05/25/12 06:51pm

I can't speak for the Anderson hitch since I run an Equalizer, but do have experience with the OEM Suburban hitch. I never noticed any issues when I had our Jayco hybrid which was much much lighter. Our new Cougar has a loaded tongue weight north of 1000lbs. I noticed after initially adjusting the WD bars for the new trailer I had a troubling amount of flex from the GM hitch. When the WD bars were loaded, the pin box was obviously not vertical, but tilted up a troubling amount. Would it have failed? I was not going to risk it. My hitch honestly looked to be in great condition with almost no rust but I installed a Reese Titan any way. In addition to being a stronger hitch, the mounting bars are almost twice as long as the OEM hitch. This will distribute forces over more of the frame which will also increase strength. After spending $25000 on a new trailer.... a $300 hitch was cheap insurance.

Also, after installing the Titan I had no more pin box flex. I am not sure how GM felt comfortable putting a 1200LB rating on this hitch. Sorry for the long rant but I just went through this two weeks ago so it is still fresh in my head!

Best of luck to you!

2012 Keystone Cougar 31SQB
2004 Suburban 2500 8.1l 4.10
ProPride
Prodigy P2
Reese Titan Hitch

Posted By: Ron Gratz on 05/25/12 07:27pm

BarneyS wrote:

Ron, Even if it were caused by a pivot projection hitch, the receiver should not have failed. I think that is the point that Ben is making.---

Barney, I don't know what point Ben is making. All I know is what he posted:

BenK wrote:

If GMT800 (2000-2006), then the receiver should be replaced with a proper one. The OEM receiver bends and consume WD forces. So it DOES NOT transfer as much weight to the front axle as a traditional receiver would with the same WD spring forces

BenK wrote:

What happens is that the receiver pin box assembly bends on the round cross bar to 'consume' WD forces till it reaches its limits...then it will transfer (distribute) the WD forces. There are a multitude of other issues with that design

Renojack asked, "Where does the claim that the stock Chevy hitch absorbs weight distribution come from." (bold added for emphasis) Renojack's posts are about weight distribution, and it is clear from his scales data that he simply does not have his chains sufficiently tensioned. IMO, his problem is not the receiver -- he simply needs to tighten the nuts.

Receivers do not 'consume' WD forces. Suggesting that his receiver needs to be replaced because the round cross bar 'consumes' WD forces is not going to solve his problem, IMO.

Ron

Posted By: BarneyS on 05/25/12 07:35pm

Ron, I learned long ago not to try to argue a point with you ( [emoticon]

) BUT notice that Ben said "So it DOES NOT transfer as much weight to the front axle as a traditional receiver would with the same WD spring forces." (Bold added for emphasis) I still think his point was valid. [emoticon]

Who knows what is going to solve the OP's problem. It could very well be that he simply needs to tighten up his WD chains BUT it is also possible his receiver is bending like so many others have. It is something he should check on instead of being unaware of a possible problem.
Barney

Posted By: renojack on 05/25/12 07:54pm

I appreciate your collective concern and have a list of things,(all valid suggestions) to check on before my next trip. Thank you all.

Renojack

RENOJACK
"The journey IS the destination"
2014 Denali 287RE TT
NV Plate "THETRLR"
2016 Ram 2500 Laramie Cummins 6.7
NV Plate "THE RAM"
Equalizer 1400#

Posted By: PHS79 on 05/25/12 08:14pm

renojack, with as heavy as your trailer is I would try using atleast 1/4" of compression of the bushings which was roughly 9 threads. With only 7 thread you aren't getting anywhere near enough compression on the bushings to transfer the weight.

On my F150/Grey Wolf 26BH combo (with 650-700lb tongue weight), compressing the bushings 1/4" raised the rear of my truck to with-in about 1/4-3/8" of the unloaded height and dropped the front end 1/8" from the unloaded height. I don't have a scale locally, but just by taking measurements it is quiet evident that the hitch did transfer a good amount of weight on my truck.

Instead of counting threads I always measure the bushing. To me its a lot more accurate way of getting the same tension and WD with this hitch.

2004 F150 FX4, with lots of mods and way too much money dumped into the truck for said mods
2013 Passport 3220BH
old TTs:
2012 Grey Wolf 26BH
2001 Kodiak K215

Posted By: Ron Gratz on 05/25/12 08:19pm

BarneyS wrote:

Ron, I learned long ago not to try to argue a point with you ( [emoticon]

If the "WD spring forces" are the same, the load transfer to the front axle will be the same
-- unless you change WD bar length, TV wheelbase, ball overhang, ball to TT axles distance, or tongue weight.
Receiver torsional stiffness does not enter into the relationship between WD spring force and load transfer.

Quote:

---BUT it is also possible his receiver is bending like so many others have. It is something he should check on instead of being unaware of a possible problem.

The amount of receiver rotation which would result in being able to transfer only 40# to the front axle would be so great as to be easily detected.
And, IMO, there would have to be some major cracking.
renojack stated he had the receiver checked and all was in order as far as loose or cracked welds.

I think we should wait to see what happens after he gets the compression charts from Andersen.

Ron

Posted By: BarneyS on 05/26/12 07:42am

Ron,
Let me rephrase what you just posted to make sure I understand exactly what you are saying.
With 5 links under tension and everything remaining the same (rear overhang etc.) you will get the SAME weight transfer to the front axles of the tow vehicle regardless of whether the receiver bends upwards or not when the WD force is applied.

Is this an accurate statement of what you are saying in your post above? If so, then it is contrary to what I have thought all along and I have learned something new today.
Barney

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